How about a -- "Sound Pressure Level"?
--? Before & After comparison?
Regards,
John
Georgia USA
On 4/5/2020 6:19 PM, Barry McDOwell
wrote:
Very nice John, great machining as always. ?Like Charles will
be interested to see if quieter and by how much.
Barry
Australia?
Hi, John,
I am very much looking forward to hearing if they are actually
quieter, once installed. Very nice machining job, as usual!
--
Regards,
Charlie
New Jersey, USA
LAW OF ANNOYANCE: When working on a project,
if you put away a tool that you’re certain you’re
finished with, you will need it instantly.
?
?
New H/L mini
lathe gears.
Recently?
cut new aluminium H/L headstock gears, I replaced the nylon
gears to steel some years ago,?
after
breaking several sets, the?steel worked OK but were very
noisy.
The
new "ally" gears cut are a smidge larger in tooth contact to
take up the back lash between teeth.
Hope to strip the lathe down and fit gears when it gets
warmer, to cold here to tinker at this moment.
See
photo, hope?of interest.
--
John
|
Very nice John, great machining as always. ?Like Charles will be interested to see if quieter and by how much.
Barry Australia?
toggle quoted message
Show quoted text
On 6 Apr 2020, at 05:55, CLevinski < clevinski@...> wrote: Hi, John, I am very much looking forward to hearing if they are actually quieter, once installed. Very nice machining job, as usual! -- Regards, Charlie New Jersey, USA
LAW OF ANNOYANCE: When working on a project, if you put away a tool that you’re certain you’re finished with, you will need it instantly.
|
Hi, John, I am very much looking forward to hearing if they are actually quieter, once installed. Very nice machining job, as usual! -- Regards, Charlie New Jersey, USA
LAW OF ANNOYANCE: When working on a project, if you put away a tool that you’re certain you’re finished with, you will need it instantly.
|
toggle quoted message
Show quoted text
From: [email protected] [mailto:[email protected]] On Behalf Of John Lindo
Sent: April-05-20 4:33 AM
To: [email protected]
Subject: [digitalhobbyist] #LATHES? New H/L mini lathe gears. Recently? cut new aluminium H/L headstock gears, I replaced the nylon gears to steel some years ago,? after breaking several sets, the?steel worked OK but were very noisy. The new "ally" gears cut are a smidge larger in tooth contact to take up the back lash between teeth.
Hope to strip the lathe down and fit gears when it gets warmer, to cold here to tinker at this moment. See photo, hope?of interest.
--
John
|
New H/L mini lathe gears.
Recently? cut new aluminium H/L headstock gears, I replaced the nylon gears to steel some years ago,?
after breaking several sets, the?steel worked OK but were very noisy.
The new "ally" gears cut are a smidge larger in tooth contact to take up the back lash between teeth.
Hope to strip the lathe down and fit gears when it gets warmer, to cold here to tinker at this moment.
See photo, hope?of interest.
-- John
|
Lewis
Very well done re 3D printing and a big thanks I am sure from the front line medics.
--
John
|
I am enjoying my isolation in the garden!
Ralph
Thanks John? We're locked tightly in the house here in eastern Canada and coordinating the 3d printing of face shields for 100s of ER doctors.? I can read about other stuff at the moment but can't seem to get into the workshop to do anything at the moment !? Keep the chatter going guys I love just being able to see what others are doing. Lewis I wish all forum members and families, and the total world population the very best of health during this tragic epidemic.
We have NO boundaries that this virus will not find a way to get at us.
Please stay whenever possible at home, and we will get through this albeit slowly.
This forum has members from all over the world and I am sure our heartfelt sympathies go out to all people that are currently suffering and or have lost
(died) dear friends and family members prematurely. All so very sad.
As many of us may have extra spare time on our hands during these unprecedented "lock downs"? lets get more involved with postings of questions and answers on any
subjects listed in the # tags. and we can always add to the list if new subjects arise. We all need to innovate at this moment.
So please be aware, alert, try and stay at home and we will beat this awful virus.
A massive thanks to all the world health workers, who are putting there lives at risk to save us.?
--
John
--
Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill press, 40 watt laser, Consew brushless DC motors and a non working 3D printer
|
Thanks John? We're locked tightly in the house here in eastern Canada and coordinating the 3d printing of face shields for 100s of ER doctors. ?I can read about other stuff at the moment but can't seem to get into the workshop to do anything at the moment ! ?Keep the chatter going guys I love just being able to see what others are doing. Lewis
toggle quoted message
Show quoted text
On Mar 31, 2020, at 2:39 PM, John Lindo < bechetboat@...> wrote: I wish all forum members and families, and the total world population the very best of health during this tragic epidemic.
We have NO boundaries that this virus will not find a way to get at us.
Please stay whenever possible at home, and we will get through this albeit slowly.
This forum has members from all over the world and I am sure our heartfelt sympathies go out to all people that are currently suffering and or have lost
(died) dear friends and family members prematurely. All so very sad.
As many of us may have extra spare time on our hands during these unprecedented "lock downs"? lets get more involved with postings of questions and answers on any
subjects listed in the # tags. and we can always add to the list if new subjects arise. We all need to innovate at this moment.
So please be aware, alert, try and stay at home and we will beat this awful virus.
A massive thanks to all the world health workers, who are putting there lives at risk to save us.?
--
John
|
I wish all forum members and families, and the total world population the very best of health during this tragic epidemic.
We have NO boundaries that this virus will not find a way to get at us.
Please stay whenever possible at home, and we will get through this albeit slowly.
This forum has members from all over the world and I am sure our heartfelt sympathies go out to all people that are currently suffering and or have lost
(died) dear friends and family members prematurely. All so very sad.
As many of us may have extra spare time on our hands during these unprecedented "lock downs"? lets get more involved with postings of questions and answers on any
subjects listed in the # tags. and we can always add to the list if new subjects arise. We all need to innovate at this moment.
So please be aware, alert, try and stay at home and we will beat this awful virus.
A massive thanks to all the world health workers, who are putting there lives at risk to save us.?
--
John
|
Re: #MISC Something different.
#MISC
I’ve got one too. But I’m left handed ! And need one.
|
Do you have a DRO on your mill?? ?If you do you could whip up a couple of Arduino stepper drive controllers that just give you variable speed and use them as power feed controllers. ? If not then there are? few approaches. ?For sure you want to purchase some sort of Break Out Board so you can run your wiring once and then not have to change it.? For my CNC Router I went PMDX-125 and MACH3.? And immediately found I wanted a USB SmoothStepper for which the PMDX is already wired for. ? Without the DROs you really want some sort of display so you can move to positions.? I can't ever see using a CNC router manually.? It would be like trying to 3D print manually. ? But a mill starts out as something that can be worked with manually.? And so a PC with either MACH or LinuxCNC becomes the simplest. And MACH3 is really easy to set up if you have a parallel port.? LinuxCNC less so but it's possible.? With LinuxCNC and MESA you can either go with the 7i92H for about $89 and into any old Break Out Board
? or the 7i95 for $295.?
? A number of people swear by these
? It's ready to go but small screen and although the users claim support is good I don't have any knowledge of that.? A 3 axis system with DHL shipping arriving in about a week is about $300 Cdn plus any taxes that might be payable.? Connect to your stepper drivers and you are good to go.? ? The $295 US MESA solution still requires a PC.? But only one with Ethernet and I suspect even an older ?laptop would work with this running LinuxCNC.? Heck nowadays laptops are available for a few hundred dollars.? ?But for me in Canada with shipping I think total outlay would be closer to $500 Cdn. without the PC.? The down side is the steep learning curve for LinuxCNC.? The up side is there are lots of people using it.? ? Alternatively with MACH4 and an Ethernet Smooth Stepper or there are others now, my outlay would also approach $500.? You still need some sort of Break Out Board. ? Then there's this project from three years ago but he changed over to LinuxCNC from the BeagleBone MachineKit.? But I don't think he offers any for sale.? You'd have to build it all yourself. ? From his posting: This was my take which I used for 12 months before switching to Linuxcnc The cape connects directly to the BBB and the 2 other boards connect via a short 26 way cable ? ? ? ? What I'd like to build is something like the Chinese CNC controller but with that Ethernet connection to LinuxCNC.? Bt at $300 Cdn I'd spend more than that just building the first prototype. ?And unlike my ELS which I wanted for my Gingery Lathe so I could thread, I now have CNC on the mill and an ELS on a Southbend.? ? So needless to say I'm still thinking about all of this. ? Feel more confused? John ? ? ? ?
toggle quoted message
Show quoted text
From: [email protected] [mailto:[email protected]] On Behalf Of Bob T
Sent: March-28-20 4:54 PM
To: [email protected]
Subject: [digitalhobbyist] Low cost drive for my mill? Hi John and everyone,
As you can see, I’ve just added a brute (12nm @ 6amps) of a stepper motor to my mill. The question that I have is what is the easiest / cheapest way of providing a digital drive to it ? I have the stepper motor driver for it, ?all (!) I need is the clever stuff. What I going to do for the moment (because I have the bits in my box) is to use a XR8038 chip to provide a variable frequency, and an old Schnieder baby PLC (Zelio) ?to handle the logic. I would like to be able to handle, backlash , use an encoder or similar to move the mill by small but accurate amounts, have different speeds left and right, mill to a point and return, etc, etc. All nice to have but who’s done what ? And how did it work. I suppose I could look at something PC based, I have a couple of old HP 7900 ultra slimline boxes that would work if they’re fast enough.?
So John D. And friends please what do you suggest ?
Bob
|
Hi John and everyone,  As you can see, I’ve just added a brute (12nm @ 6amps) of a stepper motor to my mill. The question that I have is what is the easiest / cheapest way of providing a digital drive to it ? I have the stepper motor driver for it, ?all (!) I need is the clever stuff. What I going to do for the moment (because I have the bits in my box) is to use a XR8038 chip to provide a variable frequency, and an old Schnieder baby PLC (Zelio) ?to handle the logic. I would like to be able to handle, backlash , use an encoder or similar to move the mill by small but accurate amounts, have different speeds left and right, mill to a point and return, etc, etc. All nice to have but who’s done what ? And how did it work. I suppose I could look at something PC based, I have a couple of old HP 7900 ultra slimline boxes that would work if they’re fast enough.? So John D. And friends please what do you suggest ? Bob
|
Re: #LATHES Spindle Encoder Update
#LATHES
Hi Ralph, This is an area where ....angels fear to tread. From your picture it would seem that you either have an AC drive or a stepper motor drive. Either is not good from a noise point of view, but the AC servo is much worse. If, and if my guess is correct, the switched waveform drive to the motor windings is coupling into the motor via the winding capacitance in the motor. Since the the motor is “parked” on a desk top with nothing to ground the capacitive current the AC switching noise may be then coupling through the encoder and causing interference. Since the frequency’s involved are up in the R.F. Regions (we are looking at the frequency’s present in the rising and falling edges of the motor drive waveform) the length of any ground wire becomes critical ( a metre or 3 feet may be too much). The best you can do when testing like this is to run a earth wire from the earth of the drive module drive to the motor casing and keep all of the wires short. Then if you can sit the motor on (say) the lathe bed so that steel touches steel things should be better. A separate short earth from the negative of the encoder supply to ground will also help. Normally when the motor is in its correct position and bolted to earth, all will be well, ?but for now, testing like this you may not be helping yourself. It’s capacitive coupling that may be causing the issue. One job that I had was bad enough that even with the drive motor earthed ( think 13000 HP) the capacitive current through the encoder bearings was enough to destroy them in a few days. The solution was to connect the encoder to the main motor via an insulating collar, and separately earth the encoder body. Anyway this may not be your problem, but its fairly simple to try. Regards Bob
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Show quoted text
On 23 Mar 2020, at 01:09, Ralph Hulslander <rhulslander@...> wrote:
? Thanks Bob, that is interesting. I tried looking at the encoder signal with my oscilloscope,?which I do not know how to use, and the signal looked really messy, not clear steps as expected.
re: Grounding the motor is that Earth ground or Com, possible that might explain the problem I am having.
The encoder is on the wire side of the motor, would it help to move to the other side?
Ralph On Sat, Mar 21, 2020 at 11:36 PM Bob T < zs6bxi@...> wrote: Yes that would work Ralph !? Of course you then might have to worry about getting the grounding of the motor really sorted to stop coupling of the drive power signals into the encoder. I’ve spend most of my 45 years or so working life doing drives and feedback systems ( most of them very large in size 1 ~ 10 MW). And I’m always surprised how Murphy manages to get in the way. The latest digital drives are no exception.....when someone gets the order of the running of the subroutines wrong the drive still works but the response is just horrible.? Regards Bob ? Thanks for the replies, and everyone is welcome to jump in. Bob my encoder is mounted directly on my motor.? <IMG_20200321_102907196.jpg>
Ralph On Fri, Mar 20, 2020 at 10:24 PM Bob T < zs6bxi@...> wrote: Hi Ralph, excuse me but I have been “lurking” on this thread and wanted to add to the discussion. It’s quite possible that a chunk of your jitter problems are coming from your method of driving the encoder ! Any time that one can see the belt “flapping” or moving around its a good sign that the encoder is speeding up and slowing down during each revolution. Normal V belts are very bad at this. The poly V belts are much better. The toothed belt drives CAN be very good. Direct connection with the spindle of the encoder clamped into an inline hole on the drive/chuck is the best. But with the body of the encoder stopped from spinning only by a torque arm connection. The torque arm should be of two parts. One connected to the encoder and the other via a rose joint or similar to the steel work. The two should be at 90 degrees to each other. The longer they are, the less wobble in the encoder feedback will be seen. Regards Bob ? I have not found any that just work! At best, if they show RPM they do not show the same rpm with a steady running motor. A few do not show anything.?
I do not "think" I need to be concerned with rotation, especially with my lathe, the chuck might unscrew if I tried to do any work in reverse.
My desk?time and shop time is just about over, yesterday I was already doing Honeydos in the garden. I had thought I could make it to April 1 but the garden is calling, and I like to eat it's produce.
I also am having problems with dependable repeatable stepper motor code.
Of course I am not a programmer.
Ralph On Fri, Mar 20, 2020 at 12:11 PM CLevinski < clevinski@...> wrote: Ralph,
Ah, I couldn't see that before. It looked like it was direct mounted. Good job!
No, I don't have a program that will read the encoder, but it should be fairly simple. Are you concerned about direction of rotation? What problems have you encountered with trying to read the encoder to date?
--
Regards,
Charlie
New Jersey, USA
LAW OF ANNOYANCE: When working on a project, if you put away a tool that you’re certain you’re finished with, you will need it instantly.
-- Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill press, 40 watt laser, Consew brushless DC motors and a non working 3D printer
-- Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill press, 40 watt laser, Consew brushless DC motors and a non working 3D printer
-- Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill press, 40 watt laser, Consew brushless DC motors and a non working 3D printer
|
Thanks John, just had a lightbulb moment it is starting to sink in.
On Sat, Mar 21, 2020 at 12:58 PM John Dammeyer < johnd@...> wrote: See below. ? ? John D sharing his spindle encoder speed to leadscrew stepper has me thinking, actually I have been mystified/wondering about this for a long time.
This is a question.
If I have a 8tpi (thread per inch) leadscrew and I want to thread 1" rod at 8tpi with 100 rpm at the spindle the leadscrew has to rotate 100 rpm? ? Yes.? Lead screw pitch is done with the lead screw turning the same speed as the spindle.
What would the leadscrew rpm be at 1,000 rpm spindle speed? What would the SFM (Surface Feet per Minute) be?
? It would be 1000 RPM.? The SFM is dependent on the diameter that is getting the lead screw pitch.? The pitch and the diameter are mutually exclusive.? My ELS will tell you the SFM instead of RPM if you set the parameters.? The math is actually pretty simple.
I am looking at a and getting more confused.
With Tool Steel at 75 -175 SFM? that seems the leadscrew would be in the 1,000s of rpm.
2 x PI x r is the circumference of a circle.? Or PI x d.? So a 1" bar stock has 3.14" circumference or if you divide that value by 12"/Foot you get 0.261799388 feet.? ? If it's turning 100 RPM then it's ? 0.261799388 ft * 100 RPM = 26 SFM ? At 1000 RPM it's 262 SFM. ? Run the spindle at 650 RPM and your SFM is 170.? That's for 1" bar stock. ? You have to excuse me I am completely self taught, I flunked out of Machine Shop II 55 years ago
and have not touch a machine tool since. ? There are some basic math operations that you need to be able to do or use some sort of calculator program like this one.
? So let's say you have some 1/4" rod that you want to thread at 20 TPI because it's Sunday evening and the hardware store that sells all-thread rod is closed. ? Diameter is 0.25" Your lead screw is 8 TPI and the spindle is 1:1 for lead screw threads.? ? 20/8 = 2.5 so the lead spindle has to turn 2.5x as fast as the lead screw.? Or to put it another way.? The leadscrew pitch is 0.125" and you want 0.05" pitch so for each turn of the spindle you want 0.05" movement of the lead screw which is 0.125/0.05=2.5. ? So if your spindle speed is 1000 RPM then the leadscrew turns 400 RPM.? But what about SFM?? Using the calculator above I select tool diameter 0.25", 75 as the minimum SFM and it tells me 1145 RPM.? And this is where a smaller higher speed lathe is so much handier with the mid range of 125 SFM you get 1910 RPM. ? But if it's a short thread that's really fast for engaging the half nut so most people will turn that more slowly or just use a die.
There are no classes nearby and the only local machinist I know of, are those I go to their yard sales
when they are dead and the shops are being sold off.
This is why we have the forums, which I am so thankful for.
Ralph
--
Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill press, 40 watt laser, Consew brushless DC motors and a non working 3D printer
--
Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill press, 40 watt laser, Consew brushless DC motors and a non working 3D printer
|
Re: #LATHES Spindle Encoder Update
#LATHES
Thanks Bob, that is interesting. I tried looking at the encoder signal with my oscilloscope,?which I do not know how to use, and the signal looked really messy, not clear steps as expected.
re: Grounding the motor is that Earth ground or Com, possible that might explain the problem I am having.
The encoder is on the wire side of the motor, would it help to move to the other side?
Ralph
On Sat, Mar 21, 2020 at 11:36 PM Bob T < zs6bxi@...> wrote: Yes that would work Ralph !? Of course you then might have to worry about getting the grounding of the motor really sorted to stop coupling of the drive power signals into the encoder. I’ve spend most of my 45 years or so working life doing drives and feedback systems ( most of them very large in size 1 ~ 10 MW). And I’m always surprised how Murphy manages to get in the way. The latest digital drives are no exception.....when someone gets the order of the running of the subroutines wrong the drive still works but the response is just horrible.? Regards Bob ? Thanks for the replies, and everyone is welcome to jump in. Bob my encoder is mounted directly on my motor.? <IMG_20200321_102907196.jpg>
Ralph On Fri, Mar 20, 2020 at 10:24 PM Bob T < zs6bxi@...> wrote: Hi Ralph, excuse me but I have been “lurking” on this thread and wanted to add to the discussion. It’s quite possible that a chunk of your jitter problems are coming from your method of driving the encoder ! Any time that one can see the belt “flapping” or moving around its a good sign that the encoder is speeding up and slowing down during each revolution. Normal V belts are very bad at this. The poly V belts are much better. The toothed belt drives CAN be very good. Direct connection with the spindle of the encoder clamped into an inline hole on the drive/chuck is the best. But with the body of the encoder stopped from spinning only by a torque arm connection. The torque arm should be of two parts. One connected to the encoder and the other via a rose joint or similar to the steel work. The two should be at 90 degrees to each other. The longer they are, the less wobble in the encoder feedback will be seen. Regards Bob ? I have not found any that just work! At best, if they show RPM they do not show the same rpm with a steady running motor. A few do not show anything.?
I do not "think" I need to be concerned with rotation, especially with my lathe, the chuck might unscrew if I tried to do any work in reverse.
My desk?time and shop time is just about over, yesterday I was already doing Honeydos in the garden. I had thought I could make it to April 1 but the garden is calling, and I like to eat it's produce.
I also am having problems with dependable repeatable stepper motor code.
Of course I am not a programmer.
Ralph On Fri, Mar 20, 2020 at 12:11 PM CLevinski < clevinski@...> wrote: Ralph,
Ah, I couldn't see that before. It looked like it was direct mounted. Good job!
No, I don't have a program that will read the encoder, but it should be fairly simple. Are you concerned about direction of rotation? What problems have you encountered with trying to read the encoder to date?
--
Regards,
Charlie
New Jersey, USA
LAW OF ANNOYANCE: When working on a project, if you put away a tool that you’re certain you’re finished with, you will need it instantly.
-- Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill press, 40 watt laser, Consew brushless DC motors and a non working 3D printer
-- Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill press, 40 watt laser, Consew brushless DC motors and a non working 3D printer
--
Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill press, 40 watt laser, Consew brushless DC motors and a non working 3D printer
|
Re: #LATHES Spindle Encoder Update
#LATHES
Yes that would work Ralph !? Of course you then might have to worry about getting the grounding of the motor really sorted to stop coupling of the drive power signals into the encoder. I’ve spend most of my 45 years or so working life doing drives and feedback systems ( most of them very large in size 1 ~ 10 MW). And I’m always surprised how Murphy manages to get in the way. The latest digital drives are no exception.....when someone gets the order of the running of the subroutines wrong the drive still works but the response is just horrible.? Regards Bob
toggle quoted message
Show quoted text
On 22 Mar 2020, at 00:33, Ralph Hulslander <rhulslander@...> wrote:
? Thanks for the replies, and everyone is welcome to jump in. Bob my encoder is mounted directly on my motor.? <IMG_20200321_102907196.jpg>
Ralph On Fri, Mar 20, 2020 at 10:24 PM Bob T < zs6bxi@...> wrote: Hi Ralph, excuse me but I have been “lurking” on this thread and wanted to add to the discussion. It’s quite possible that a chunk of your jitter problems are coming from your method of driving the encoder ! Any time that one can see the belt “flapping” or moving around its a good sign that the encoder is speeding up and slowing down during each revolution. Normal V belts are very bad at this. The poly V belts are much better. The toothed belt drives CAN be very good. Direct connection with the spindle of the encoder clamped into an inline hole on the drive/chuck is the best. But with the body of the encoder stopped from spinning only by a torque arm connection. The torque arm should be of two parts. One connected to the encoder and the other via a rose joint or similar to the steel work. The two should be at 90 degrees to each other. The longer they are, the less wobble in the encoder feedback will be seen. Regards Bob ? I have not found any that just work! At best, if they show RPM they do not show the same rpm with a steady running motor. A few do not show anything.?
I do not "think" I need to be concerned with rotation, especially with my lathe, the chuck might unscrew if I tried to do any work in reverse.
My desk?time and shop time is just about over, yesterday I was already doing Honeydos in the garden. I had thought I could make it to April 1 but the garden is calling, and I like to eat it's produce.
I also am having problems with dependable repeatable stepper motor code.
Of course I am not a programmer.
Ralph On Fri, Mar 20, 2020 at 12:11 PM CLevinski < clevinski@...> wrote: Ralph,
Ah, I couldn't see that before. It looked like it was direct mounted. Good job!
No, I don't have a program that will read the encoder, but it should be fairly simple. Are you concerned about direction of rotation? What problems have you encountered with trying to read the encoder to date?
--
Regards,
Charlie
New Jersey, USA
LAW OF ANNOYANCE: When working on a project, if you put away a tool that you’re certain you’re finished with, you will need it instantly.
-- Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill press, 40 watt laser, Consew brushless DC motors and a non working 3D printer
-- Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill press, 40 watt laser, Consew brushless DC motors and a non working 3D printer
|
toggle quoted message
Show quoted text
From: [email protected] [mailto:[email protected]] On Behalf Of Ralph Hulslander
Sent: March-21-20 8:46 AM
To: [email protected]
Subject: [digitalhobbyist] Spindle speeds? John D sharing his spindle encoder speed to leadscrew stepper has me thinking, actually I have been mystified/wondering about this for a long time.
This is a question.
If I have a 8tpi (thread per inch) leadscrew and I want to thread 1" rod at 8tpi with 100 rpm at the spindle the leadscrew has to rotate 100 rpm? ? Yes.? Lead screw pitch is done with the lead screw turning the same speed as the spindle.
What would the leadscrew rpm be at 1,000 rpm spindle speed? What would the SFM (Surface Feet per Minute) be?
? It would be 1000 RPM.? The SFM is dependent on the diameter that is getting the lead screw pitch.? The pitch and the diameter are mutually exclusive.? My ELS will tell you the SFM instead of RPM if you set the parameters.? The math is actually pretty simple.
I am looking at a and getting more confused.
With Tool Steel at 75 -175 SFM? that seems the leadscrew would be in the 1,000s of rpm.
2 x PI x r is the circumference of a circle.? Or PI x d.? So a 1" bar stock has 3.14" circumference or if you divide that value by 12"/Foot you get 0.261799388 feet.? ? If it's turning 100 RPM then it's ? 0.261799388 ft * 100 RPM = 26 SFM ? At 1000 RPM it's 262 SFM. ? Run the spindle at 650 RPM and your SFM is 170.? That's for 1" bar stock. ? You have to excuse me I am completely self taught, I flunked out of Machine Shop II 55 years ago
and have not touch a machine tool since. ? There are some basic math operations that you need to be able to do or use some sort of calculator program like this one.
? So let's say you have some 1/4" rod that you want to thread at 20 TPI because it's Sunday evening and the hardware store that sells all-thread rod is closed. ? Diameter is 0.25" Your lead screw is 8 TPI and the spindle is 1:1 for lead screw threads.? ? 20/8 = 2.5 so the lead spindle has to turn 2.5x as fast as the lead screw.? Or to put it another way.? The leadscrew pitch is 0.125" and you want 0.05" pitch so for each turn of the spindle you want 0.05" movement of the lead screw which is 0.125/0.05=2.5. ? So if your spindle speed is 1000 RPM then the leadscrew turns 400 RPM.? But what about SFM?? Using the calculator above I select tool diameter 0.25", 75 as the minimum SFM and it tells me 1145 RPM.? And this is where a smaller higher speed lathe is so much handier with the mid range of 125 SFM you get 1910 RPM. ? But if it's a short thread that's really fast for engaging the half nut so most people will turn that more slowly or just use a die.
There are no classes nearby and the only local machinist I know of, are those I go to their yard sales
when they are dead and the shops are being sold off.
This is why we have the forums, which I am so thankful for.
Ralph
--
Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill press, 40 watt laser, Consew brushless DC motors and a non working 3D printer
|
John D sharing his spindle encoder speed to leadscrew stepper has me thinking, actually I have been mystified/wondering about this for a long time.
This is a question.
If I have a 8tpi (thread per inch) leadscrew and I want to thread 1" rod at 8tpi with 100 rpm at the spindle the leadscrew has to rotate 100 rpm?
What would the leadscrew rpm be at 1,000 rpm spindle speed? What would the SFM (Surface Feet per Minute) be?
I am looking at a and getting more confused.
With Tool Steel at 75 -175 SFM? that seems the leadscrew would be in the 1,000s of rpm.
You have to excuse me I am completely self taught, I flunked out of Machine Shop II 55 years ago
and have not touch a machine tool since.
There are no classes nearby and the only local machinist I know of, are those I go to their yard sales
when they are dead and the shops are being sold off.
This is why we have the forums, which I am so thankful for.
Ralph
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Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill press, 40 watt laser, Consew brushless DC motors and a non working 3D printer
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Re: #LATHES Spindle Encoder Update
#LATHES
Thanks for the replies, and everyone is welcome to jump in. Bob my encoder is mounted directly on my motor.?
On Fri, Mar 20, 2020 at 10:24 PM Bob T < zs6bxi@...> wrote: Hi Ralph, excuse me but I have been “lurking” on this thread and wanted to add to the discussion. It’s quite possible that a chunk of your jitter problems are coming from your method of driving the encoder ! Any time that one can see the belt “flapping” or moving around its a good sign that the encoder is speeding up and slowing down during each revolution. Normal V belts are very bad at this. The poly V belts are much better. The toothed belt drives CAN be very good. Direct connection with the spindle of the encoder clamped into an inline hole on the drive/chuck is the best. But with the body of the encoder stopped from spinning only by a torque arm connection. The torque arm should be of two parts. One connected to the encoder and the other via a rose joint or similar to the steel work. The two should be at 90 degrees to each other. The longer they are, the less wobble in the encoder feedback will be seen. Regards Bob ? I have not found any that just work! At best, if they show RPM they do not show the same rpm with a steady running motor. A few do not show anything.?
I do not "think" I need to be concerned with rotation, especially with my lathe, the chuck might unscrew if I tried to do any work in reverse.
My desk?time and shop time is just about over, yesterday I was already doing Honeydos in the garden. I had thought I could make it to April 1 but the garden is calling, and I like to eat it's produce.
I also am having problems with dependable repeatable stepper motor code.
Of course I am not a programmer.
Ralph On Fri, Mar 20, 2020 at 12:11 PM CLevinski < clevinski@...> wrote: Ralph,
Ah, I couldn't see that before. It looked like it was direct mounted. Good job!
No, I don't have a program that will read the encoder, but it should be fairly simple. Are you concerned about direction of rotation? What problems have you encountered with trying to read the encoder to date?
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Regards,
Charlie
New Jersey, USA
LAW OF ANNOYANCE: When working on a project, if you put away a tool that you’re certain you’re finished with, you will need it instantly.
-- Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill press, 40 watt laser, Consew brushless DC motors and a non working 3D printer
--
Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill press, 40 watt laser, Consew brushless DC motors and a non working 3D printer
|
Re: #LATHES Spindle Encoder Update
#LATHES
Hi Ralph, excuse me but I have been “lurking” on this thread and wanted to add to the discussion. It’s quite possible that a chunk of your jitter problems are coming from your method of driving the encoder ! Any time that one can see the belt “flapping” or moving around its a good sign that the encoder is speeding up and slowing down during each revolution. Normal V belts are very bad at this. The poly V belts are much better. The toothed belt drives CAN be very good. Direct connection with the spindle of the encoder clamped into an inline hole on the drive/chuck is the best. But with the body of the encoder stopped from spinning only by a torque arm connection. The torque arm should be of two parts. One connected to the encoder and the other via a rose joint or similar to the steel work. The two should be at 90 degrees to each other. The longer they are, the less wobble in the encoder feedback will be seen. Regards Bob
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Show quoted text
On 21 Mar 2020, at 03:19, Ralph Hulslander <rhulslander@...> wrote:
? I have not found any that just work! At best, if they show RPM they do not show the same rpm with a steady running motor. A few do not show anything.?
I do not "think" I need to be concerned with rotation, especially with my lathe, the chuck might unscrew if I tried to do any work in reverse.
My desk?time and shop time is just about over, yesterday I was already doing Honeydos in the garden. I had thought I could make it to April 1 but the garden is calling, and I like to eat it's produce.
I also am having problems with dependable repeatable stepper motor code.
Of course I am not a programmer.
Ralph On Fri, Mar 20, 2020 at 12:11 PM CLevinski < clevinski@...> wrote: Ralph,
Ah, I couldn't see that before. It looked like it was direct mounted. Good job!
No, I don't have a program that will read the encoder, but it should be fairly simple. Are you concerned about direction of rotation? What problems have you encountered with trying to read the encoder to date?
--
Regards,
Charlie
New Jersey, USA
LAW OF ANNOYANCE: When working on a project, if you put away a tool that you’re certain you’re finished with, you will need it instantly.
-- Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill press, 40 watt laser, Consew brushless DC motors and a non working 3D printer
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John Lindo
